In a typical seismic survey, a plurality of seismic sources, such as explosives, vibrators, airguns or the like, may be sequentially activated near the surface of the earth to generate energy (i.e., seismic waves) which may propagate into and through the earth. The seismic waves may be reflected back by geological formations within the earth, and the resultant seismic wave field may be sampled by a plurality of seismic receivers, such as geophones, hydrophones and the like. Each receiver may be configured to acquire seismic data at the receiver's location, normally in the form of a seismogram representing the value of some characteristic of the seismic wave field against time. The acquired seismograms or seismic data may be transmitted wirelessly or over electrical or optical cables to a recorder system. The recorder system may then store, analyze, and/or transmit the seismic data. This data may be used to generate and image of subsurface formations in the earth and may also be used to detect the possible presence of hydrocarbons, changes in the subsurface formations and the like.
In a marine seismic survey, seismic data typically include up-going waves that are reflected off of the surface of the earth and down-going waves that are reflected from the sea surface. The up-going waves may be used to detect the possible presence of hydrocarbons, changes in the subsurface and the like. The down-going waves (i.e., sea-surface ghost waves), however, may destructively interfere with the up-going waves at certain frequencies such that the up-going waves are completely canceled out of the seismic data.
In some situations, using a coil-oriented sail path for marine seismic surveys can be beneficial and more efficient than traditional straight sail lines for acquisition. Moreover, having a streamer array that can be oriented in varying geometries, such as varying streamer depths, during a coil-based marine survey can have additional benefits over traditional marine surveys.
Accordingly, there is a need for methods and systems that can employ faster, more efficient and more accurate marine surveys, such as coil-based acquisition in varying configurations. Such methods and systems may complement or replace conventional methods and systems for marine surveys.